The present invention relates to a semiconductor device and a method of manufacturing the semiconductor device. For example, the invention can be preferably applied to a semiconductor device using a nitride semiconductor.
GaN-based nitride semiconductor is expected to be used for a transistor in applications of high withstand voltage, high output, and high frequency because of its wide bandgap and high electron mobility compared with Si or GaAs, and has been actively developed in recent years. Among such transistors, a transistor having normally-off characteristics is useful, and a structure of the transistor is earnestly investigated so as to have the normally-off characteristics.
For example, Japanese Unexamined Patent Application Publication No. 2013-065649 discloses a transistor using a nitride semiconductor layer as a channel. In this transistor, two-dimensional electron gas (2DEG) is generated at an interface between a barrier layer and a channel layer. A mesa part is provided below a gate electrode to suppress generation of the 2DEG.